This invention relates to plastic pipe or tile laying apparatus, and more particularly to a continuous corrugated tile laying apparatus which is atttched to a trench digging machine.
Perforated corrugated drainage pipe, or tile, as it is commonly referred to, is frequently utilized in areas where normal water drainage is insufficient for the land use desired. Improved drainage is conventionally obtained by laying tile in a sub-surface position by means of a trench digging machine and an associated tile layer. The trenching machine digs the trench while the following tile layer places the tile at the trench bottom. Thereafter, the trench is backfilled, thus holding the laid tile as the layer moves on down the trench. The secured or laid tile pulls tile from the layer as the layer progresses.
Conventional tile layers have been in use for some time, however, such layers are attended by a number of problems and disadvantages which makes their was difficult. For example, the known layers in use tend to exert a great deal of frictional force on the tile as it passes through the layer. It accordingly may require a pulling force on the order of 100 pounds to pull the tile through the layer. Excessive pulling forces exerted on the tile as the layer moves down the trench can stretch or cause deformation of the tile.
Moreover, these frictional forces in known layers must be dealt with when loading and unloading the layer. This makes both loading and unloading the layer a difficult task. Great forces must be used to pull the tile through the layer to load or unload it.
Also, in the laying operation, it is common for the trencher to engage obstructions, such as rocks. When the trencher encounters such an obstruction, the trencher and associated layer must be lifted out of the trench so that the obstruction can be removed. This places substantial bending pressures on the tile and can cause it to deform or split.
Specifically, as the layer is lifted away from the trench bottom, the placed tile pulls tile through the layer, against the frictional forces mentioned, and can cause undesirable stretching or failure of the tile. Ordinarily, the current practice is thus to cut the tile, in order to lift the trencher. This necessitates splicing the tile ends back together when laying is resumed.
Still further, the known current layers are primarily adapted for laying of only one kind of tile, such as the round corrugated variety. Such layers are consequently limited in their usefulness where tile cost and availability, or terrain dictate a different size or type of tile.
Tile primarily comes in one type, i.e., corrugated, perforated, circular cross section, plastic conduit of several different sizes. The circumferential corrugations provide flexibility such that the tile can be wound on large rolls, from which it is fed into the tile layer, while producing substantial resistance to crushing when the tile us buried.
Another form of tile is the type known as "arched" tile. Such a tile is semi-circular, or arched, in upper cross section, and has a flat, flexible floor extending as a diametral chord between the ends of the semi-circular or arched portion.
The arched portion is longitudinally hinged at the arch apex so the side portions of the arch can be folded inwardly together, with the flexible floor preferably folding inwardly toward the apex. Both the arched portion and the floor can be perforated, or only the floor is perforated, as desired, for the ingress of water into the tile from the floor of the trench in which the tile is laid.
Arched tile has the advantage of being collapsible, and can be folded upon itself by forcing the flat bottom upwardly into the apex of the curved portion. More arced tile can consequently be wound on a given roll.
Nevertheless, the laying of such arched tile presents additional necessary functions for the tile layer since the tile not only must be laid in the trench, but it must be erected or unfolded as well as it moves through the layer. Layers for round tile are thus not useful for laying arched tile since there are no provisions for erecting the arch tile, or for maintaining it in position without flipping or turning in the layer.
Accordingly, it is one objective of this invention to provide an improved tile layer.
Another objective of the invention is to provide a tile layer having simple access to its interior such that the tile can be placed into and removed from the layer with little or no load or pull force thereby imposed upon the tile.
Another objective of the invention is to provide a tile layer from which tile can be removed during the tile laying operation in order to permit removal of the trencher and related layer mechanism without disturbing the laid tile, and with little or no bending force applied to the tile.
Yet another objective is to provide a tile layer capable of handling various types of tile, including both corrugated round and arched tile, as well as round tile of varying diameters.